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Dairy notes January 04

REARING HEALTHY CALVES

Calving rearing is among the most important jobs on the dairy farm and the key to success lies in good stockmanship. Ideally the same person should be responsible for the care and feeding of calves on a daily basis. The calf should, in its first eight weeks of life be given every opportunity to thrive and grow in a healthy environment.

DISEASE PROBLEMS
It is estimated that 5% of all calves born alive die before they reach six months of age. The highest level of mortality is within their first two weeks. Scours and respiratory problems are the two major causes of illness. As many as one in five of all calves are affected by scours in their first few days. Good management and preventative measures against calf sours include:
  • feeding adequate and timely colostrums
  • ensuring strict hygiene conditions
  • minimising stress
  • isolating sick calves
  • taking care with bought-in calves
  • avoiding sudden changes to diets.
The main respiratory problem is pneumonia and is generally caused by unsatisfactory housing conditions where ventilation is inadequate. There are three important aspects of good ventilation in calf houses.
  • sufficient air space, allowing at least 3 cubic metres/calf
  • air movement which allows stale air to be removed from the house and replaced with fresh air. In most houses natural ventilation will allow this but in some situations controllable fans may be essential.
  • the avoidance of draughts, especially below calf head height.
Calf diseases such as scours and pneumonia have been estimated to cost as much as £30 per head in treatment and can effect productivity over the animal’s lifetime.
Good stockmanship with attention to detail, can go a long way to minimise this loss and produce healthy cattle capable of good performance.

HEAT DETECTION AND FERTILITY MANAGEMENT
A recent fertility project carried out by The Agricultural Research Institute of Northern Ireland at Hillsborough has estimated that fertility problems cost each 100 cow Northern Ireland dairy farmer between £5,000 - £10,000 every year.
HEAT DETECTION
Good heat detection depends on observation, organisation and recording. In short, management discipline has a major effect on dairy herd profitability.
Cows generally show signs of heat every 21 days but the cycles can range from 12 to 30 days. Cows show various signs of heat over a two to three day period.
The sequence of behaviour
The typical sequence of behaviour generally happens in the following order:
  • Aggressive rubbing by pairs of cows;
  • Sniffing around tailhead;
  • Chin resting;
  • Attempting to mount another animal;
  • Disorientated mounting;
  • Standing to be mounted (the key sign).
The time a cow stands to be mounted lasts for only 8 to 12 hours so frequent observation is essential.
When do signs of heat occur?
The strongest signs of heat tend to occur:
  • At night and mid afternoon in housed herds.
  • When cows are not being milked or fed.
  • When cows are not being moved.
The ideal time to inseminate is 12 to 18 hours after she first stands to be mounted.
Targets for good fertility management
A key recommendation from the Hillsborough research is that 100 day in-calf rate (for spread calving herds) should be adopted as a more appropriate and meaningful measure of overall herd fertility than calving interval. The project also concluded that the target 100-day in-calf rate for Northern Ireland dairy herds should be greater than 40% that is 40% of the herd should be in-calf by 100 days after calving.
The project findings highlight that you can improve your 100-day in-calf rate by improving both submission rates and conception rates.
Improving submission rate:
  • Undertake heat detection for 4 weeks prior to start of breeding season;
  • Use good heat detection procedures with frequent observations (4-5 times per day and 20 minutes per check) or tail paint;
  • Identify and treat non-cycling cows early (that is those not seen in heat by 42 days after calving);
  • Inseminate cows earlier than currently practised, for example from day 56 after calving onwards.
    •
    Improving conception rate:
  • Control dry cow conditions (Avoid over fat >3.0 or very thin <2.0 cows);
  • Reduce liveweight loss in early lactation by maintaining high feed intakes in early lactation;
  • Avoid major changes in diet during the breeding period;
  • Use a good AI technique (or use a trained AI inseminator).
    •
    Getting cows back in-calf to AI requires a combination of good heat observation, good conception rates and good record keeping.

    QUOTA MANAGEMENT
    Only 3 months of the quota year remain. This year’s production is running at record levels with the consequence that quota prices have soared in recent weeks. If you are running over quota, there are a number of options available to reduce production:
    • Cull cows which are giving problems for example mastitis, fertility, lameness. These cows have been ‘carried’ on many farms in recent years when there was less risk of an over-quota situation.
    • Dry off cows early. This will really only affect cows calving in April/May which would normally be dried off in February/March. This may be ‘too little, too late’ for producers with winter calving herds.
    • Feed whole milk to calves. A batch of 40 calves consuming 5 litres of whole milk per day would reduce output by 6,200 litres in January.
    • Lease/purchase additional quota
    • Amend feeding strategy. Concentrate levels can be reduced slightly to reduce production. For example a freshly-calved cow consuming 50 kgs of silage and 12 kgs of a 20% protein ration would be expected to yield approximately 35 litres/day. Reducing meal levels to 9.5 kg/day would lower production to 30 litres/day.
    Reductions in milk yield can also be achieved by reducing the protein content of the concentrates fed while maintaining the energy level. Feeding a 16 % crude protein concentrate rather than a 21% one can lead to a drop in daily milk yield by up to 20%.
    It is important to ensure that other factors are considered such as body condition, fertility status and overall herd health before taking action. Remember cows which are slowed down too much in early lactation may have difficulty picking up production again later in the spring.
    Careful budgeting is required as paying superlevy is not good financial management.

    WINTER FEEDING SYSTEMS
    Greenmount Benchmarking records the type of feeding system used across all benchmarked farms in an attempt to obtain a better understanding of the dairy production systems on typical farms. This provides a great deal of information to help understand and analysis the economic results.
    Analysis of 20 top yielding dairy herds benchmarked
    The winter feeding system on a dairy farm often has a considerable impact on both costs and output. It is also very important to consider the impact on labour costs associated with a particular feeding system. The table below shows herds that use diet feeders are larger, with an average herd size of 163 cows, compared to 85 cows in non diet fed herds. Milk yield from both systems are similar with almost equal levels of meal feeding recorded. Overhead costs are increased significantly for the diet fed herds, a consequence of higher machinery costs and depreciation. Although the diet fed herds are earning less profit per cow, on a whole herd basis the diet fed herds are more profitable due to the larger herd size.
      Diet fed herds Easy fed herds
    Cow Numbers 163 85
    Yield (litres/cow) 8267 8281
    Meal fed (kgs) 2599 2617
     
    From this comparison it would appear that depending on the individual farm circumstances regarding labour availability and finance there is a breakeven point of both cow numbers and yield per cow where a complete diet feeder can be justified.
    • Some points to remember when assessing your feeding system.
      •
      1. Higher cost systems need higher yields in order to keep the combined labour plus machinery costs under control.
      2. Are the farms feeding facilities compatible with the feed system?
      3. Yields of over 8,000 litres are being achieved without diet feeders.

    BRUCELLOSIS

    10 KEY POINTS
    Over the past six or seven years, brucellosis in cattle has been on the increase. This disease causes abortion in cattle and can be transmitted to humans through contact, setting up a debilitating disease. The most dangerous time for spread to other cattle or humans is around calving time or if there has been an abortion. It can be eradicated.
    Make these resolutions for 2004:
    1. Purchase maiden heifers from a reliable source.
    2. Isolate purchased in-calf animals and test 21 days after calving.
    3. Manage grazing to prevent spread from neighbours.
    4. Comply promptly with requests to test.
    5. Isolate all animals approaching calving.
    6. Practice hygiene at calving.
    7. Isolate aborted animals.
    8. Report ALL abortions IMMEDIATELY to your DVO.
    9. Drink only pasteurised milk.
    10. Recognise signs of disease in humans.
    Protect your cattle and your family – practise ′Fortress Farming′.
    DARD Farm Management Notes for January 2004 have been prepared by Greenmount Campus, College of Agriculture, Food and Rural Enterprise - Tel: 028 9442 6771. We acknowledge the contribution from Veterinary Service. For further information contact your local Development Adviser.
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